Variable-capacity-control compressor



Dec. 24, I929.

VARIABLE CAPACITY CONTROL COMPRESSOR Filed March 28, 1928 l-eon Buehler; J1:

L. BUEHLER, JR

m'ran STATES LEON BUEELm- 33;, OF WAYNEBBOBO, PENNSYLVANIA,

ASBIGHOB r0 imox cou- PANY, OF WAYNESIB OBO, ZPEHNSYLVANIA, A CORPORATION- VLE-CAPACITY-CONTBOL COMPRESSOR Application filed larch 28, 1928. Serial No. 265,500.

Myinvention relates to compressors for fluids having variable means for controlling their capacities.

Heretofore compressors have been provided having means for controlling capacity comprising clearance pockets communicating with the ends ofthe cylinders at the limits of the strokes of the pistons, however, with this type of device the compressors run hot unduly heating the gas and materially hampering the eficiency ofthe device.

()ne of the objects of the invention is to provide a variable'capacity control compressor which will minimize the superheating of the gas and materially increase the efiiciency oi the machine as well as efi'ect a considerable saving of fuel. I accomplish the foregoing object by placing the clearance pocket of the compressor between the limits of the stroke of the piston so that the pocket is cut ofi before the piston reaches the end of its stroke and a certain amount of gas is trapped in the cylinder between the clearance pocket and the end of the cylinder and subsequently discharged, all as will be hereinafter more particularly described and claimed.

Referring to the accompanying drawing which is made a part hereof and on which similar reference characters indicate similar parts,

The figure is a central vertical section of a compressor illustrating one application of my invention.

In the drawing reference character 10 indicates a crank case upon which a pair of cylinders 11 are mounted in upright or substantially vertical position, it being readily understood, of course," that while I have described two vertical cylinders, each provided with a clearance pocket, a single cylinder or any number desired may be used and the invention not only contemplates the arrangement of such cylinder or cylinders in vertical position, but also in horizontal or any position between the vertical and the horizontal, in any arrangement desired, as, for example, where high speed is essential, a multiplicity of cylinders may be arranged like the V-type automobile engine. Also the invention contemplates the employment not only of single acting compressors but with double acting compressors as well, the principle of course being exactly the same whether the invention is applied 'to any of the above.

Pistons 12 are disposed in the cylinders 11 such pistons being connected by means of of the cylinder and on the down stroke 0 the piston the refrigerant passes through the valve 14 into the cylinder above the end of the piston where it is compressed on the up stroke of the piston. The heads of the cylinders are provided with discharge valves 17 normally held on their seats by means of springs 18 but adapted to be forced from their seats upon the upward stroke of the piston when the gas is compressed to discharge the same in compressed condition through port 19.

In order to reduce the amount of gas discharged from the cylinders 11, I provide each of the cylinders with a clearance pocket 20 which is nothing more than an auxiliary cylinder into which a portion of the gas entrapped above the piston 12 is forced upon the upward stroke of the piston, the pressure in the clearance pocket being of course the same as that in the cylinder 11 until the piston reaches a height suflicient to cut on the clearance pocket whereupon the gas above the top of the piston will be further compressed and forced through the discharge valves and out through port 19. The clearance pocket or auxiliary cylinder 20 is provided with a piston movable therein to alter its size or shut it off entirely from the main cylinder 11 of the compressor. A head 21 forms a closure for the outer end of the clearance pocket or auxiliary cylinder 20 and in said head a threaded sleeve 22 is swivelly mounted and is provided with a polygonal head 23 at its outer end for engagement by a wrench or the like for rotatin the sleeve, such sleeve being provided wlth internal threads for cooperation with external threads 27 in the piston head 21.

. tirely so that the compressor will function the same as if the clearance pocket were not present. The piston rod 24 is provided with a projecting end 28 which is adapted to fit snugly within a seat 29 formed in the port between the vertical and horizontal cylinders.

Upon certain conditions, although not absolutely necessary, it is desirable to provide additional passages between the cylinders 11 and the clearance pockets very close to the head of the compressor. In the present instance l have provided such passages fitted with check valves 30 to permit flow from the clearance pockets to the cylinders but which prevent reversal of the flow. These passages of course are only introduced when it is found desirable or necessary to return the fluid from the clearance pockets to the cylinders before the suction valves have opened. With the wide spread use of constant speed drives, such as derived from the use of electric motors, the advantage and value of capacity control will be readily appreciated by those skilled in the art. In multistage compression it is necessary to equalize the work between the stages in order to attain maximum efficiency. Compressors fitted with my invention are well suited for such equalization or the control of multistage compression.

It will be obvious to those skilled in the art that various changes may be made in'my device without departing from the spirit of the invention, and I, therefore, do not limit myself to what is shown in the drawings and describedin the specification, but only as set forth in the appended claims.

Having thus fully described my said invention, what I claim as new and desire to secure by Letters Patent, is:

1. A. compressor for fluids comprising a vertical cylinder, a discharge valve at the end of the cylinder, a piston in said cylinder, a suction valve in the piston, a horizontal auxiliary cylinder having communication with the vertical cylinder between the limits of the stroke of the piston whereby the amount I vertical cylinder, a discharge valve at the end of the fluid discharged from the vertical gyhililder may be reduced, substantially as set ort 2. A compressor for fluids comprising a of the cylinder, a piston in said cylinder, a suctlon valve in the piston, a horizontal auxiliary c linder having communication with the vertical cylinder between the limits of the stroke of the piston, and an adjustable piston in said horizontal cylinder for reducing to a varying degree the capacity of the compressor, substantially as set forth.

3. A com ressor for fiuidscomprising a vertically disposed c linder, apiston reciprocable in said cylin er, a valve insaid 1ston, a suction port for admitting fluid into the cylinder through said valve, a valved discharge port at the op osite end of the cylinder, a horizontall isposed cylinder communicatin with t e vertical c linder between the lmits of the stroke of t e piston in the vertical cylinder, and an adjustable piston in the horizontal cylinder for varying the capacity of the gas discharged from the vertical cylinder, substantially as set forth.

4. A compressor for fluids comprising a cylinder, a piston in said cylinder, a clearance pocket having communication with the cylinder between the limits of the stroke of the piston, and a valve 'olutrolled assage between the-clearance pocket and t e cylinder permitting the passage of fluid from the clearance pocket intothe cylinder, substantially as set forth.

5. A compressor for fluids comprising a cylinder, a piston in said cylinder, a clearance pocket having communication with the cylinder between the limits of the stroke of the piston, and a valve controlled passage at a point near the discharge endof the stroke ahead of the piston permitting the passage of fluid from the clearance pocket into the cylinder, substantially as set forth.

6. A compressor for fluid comprising a main cylinder, a discharge valve at the end of the cylinder, a piston in said cylinder, a valve in the piston permitting the passage of fluid in one direction therethrough, an auxiliary cylinder having communication with the l l t main cylinder between the limits of the stroke of the piston whereby the amount of the fluid LEON BUEHLER, JR.

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